The Complexity of 2,982 Names on the September 11 Memorial

BY Elizabeth Shell  September 11, 2011 at 10:51 AM EDT

Hari Sreenivasan talked with Jer Thorp and Jake Barton about the data and design involved in arranging the 2,982 victims names on the Sept. 11 memorial at Ground Zero.

John Katsimatides, a 31-year-old corporate bonds broker for Cantor Fitzgerald, was described as the kind of person who made everyone feel like they were his best friend. Working on the 104th floor of the World Trade Center’s North Tower on Sept. 11, 2001, he was the guy everybody wanted to be around.

When the National September 11 Memorial opens Sunday a decade after the attacks, family members will for the first time be able to see the names of the victims etched in permanent relationships to those with whom they lived, worked and died.

Memorial architect Michael Arad chose not to follow the design tradition of placing names in order by letter or chronology. Rather, he envisioned each name would be arranged based on where they were and who they were with when they died. Besides known facts (if the victim was on one of the planes or worked in a particular company’s office), the memorial foundation collected more than 1,200 requests from victim’s family and friends to have names placed next to each other, creating “meaningful adjacencies” among them.

The memorial would also include the names of the six people who perished in the February, 1993 truck bombing of the World Trade Center.

To help figure out how the names would be arranged, museum and public space media design firm Local Projects was brought on.

9/11 Memorial Names An artist rendering of the 9/11 Memorial by Squared Design Lab. Image courtesy of the National September 11 Memorial & Museum.

“The architect and the Memorial had decided on this arrangement schema as a design move to try keep all the names undifferentiated,” said Jake Barton, director of Local Projects. “They wanted to make a latticework of meaning underneath all those names. You have families clustered together, best friends, even incredible stories of strangers who died on that day, all of which was identified through this process to create meaningful adjacency.”

This river of flowing names not bound by a grid or the order of the alphabet created a massively difficult data visualization problem. How could all these relationships — friends, coworkers, locations, families, travel companions, first responders — be solved? After a few computer scientists deemed the problem impossible, Barton reached out to Jer Thorp, a data visualization expert.

“I wasn’t sure that it could be done,” Thorp said. “But it was super interesting, and certainly in theory an algorithm could try and solve it.”

WTC Names Arrangement Tool from blprnt on Vimeo.

So he plugged away, trying various bits of computer programming and slowly adding in more complexity to create the step-by-step procedure for the calculations the algorithm would have to perform on all the names.

Months later, he had the custom algorithm that would create the layout and honor the adjacency requests.

“Because these are typographic elements — some are longer, some are shorter — it turns out there are elasticities in this which made it possible to solve,” Thorp said.

Jer Thorp The 9/11 names data visualization software in use. Software and photo by Jer Thorp.

Bronze parapets with the engraved names now line the two large, square pools that mark the locations of where the Twin Towers stood. Along the north pool are the names of those that died in that tower, the crew and passengers of American Airlines Flight 11, and those that died from the 1993 bombing. The south pool includes the names of those from the south tower, first responders, the crews and passengers of United Flight 175, United Flight 93 and American Airlines Flight 77, as well as victims in the Pentagon.

“Some people told me they chose to list their loved ones next to people they never would have met, but their families have [since] met and bonded,” Katsimatides said. “We’re all a part if this club we never signed up for. Twelve hundred [adjacency] requests were honored- it really, really works if you think about it.”

The memorial will be dedicated on Sept. 11, 2011, and open to the public the next day. Visitors will be able to use the 911memorial.org website, a smart phone app and kiosks at the memorial to help locate names.

Find more coverage of the 10th anniversary of the 9/11 attacks.